Flash compensation in a810

I've tried set propcase 127 - Flash Compensation in a810. The propcase is changed and used for image processing (I've compared a code piece which uses the propcase for sx150 and a810 - it is identical) but resulting Flash Bias is not recorded to exif info. So anybody knows why the propcase is not recorded to exif? For sx150 changing the propcase is written to exif fine.